After hinting last week that she may be pregnant with a Snapchat photo, tennis star Serena Williams confirmed that she is expecting in an Instagram post on Monday.

Williams' post also contains a letter to her unborn child.

My Dearest Baby,

You gave me the strength I didn’t know I had. You taught me the true meaning of serenity and peace. I can’t wait to meet you. I can’t wait for you to join the players box next year. But most importantly, I am so happy to share being number one in the world with you....once again today. On @alexisohanian bday. From the world’s oldest number one to the world’s youngest number one.

-- Your Mommy

Her announcement came on the same day the World Tennis Association released its newest rankings, which had her ranked as the top women's tennis player in the world.

Last week, Williams posted a photo of her stomach on Snapchat with the caption "20 weeks" before quickly deleting the photo. Monday's Instagram post marked the first time she had publicly addressed her pregnancy.

Williams is engaged to Reddit co-founder Alexis Ohanian. 

 

My Dearest Baby, You gave me the strength I didn’t know I had. You taught me the true meaning of serenity and peace. I can't wait to meet you. I can't wait for you to join the players box next year. But most importantly, I am so happy to share being number one in the world with you.... once again today. On @alexisohanian bday. ? from the world's oldest number one to the world's youngest number one. -Your Mommy

A post shared by Serena Williams (@serenawilliams) on

Apr 24, 2017 at 6:06am PDT

Alex Hider is a writer for the E.W. Scripps National Desk. Follow him on Twitter @alexhider.